Composition for treating metal baths and method of making the same



Patented Mar. 22, l

E, ,orr i LUBGICAL comm, on roams.

Y.. A. CORPORATION, ou wns'r vmemm.

comro snron son rnaarmciransa'ras san tation or max m THE sum.

i No Drawing.

This invention relates to the addition, to molten metal baths, of substances adapted to destroy or otherwise remove deleterious ingredients contained therein, or to add ingredients thereto, or otherwise to modify the properties of the molten metal and the solid metal to be producedtherefrom. The invention comprises methods of adding modifying materials to metal baths, compositions to be added, and methods of preparing such compositions. The -ob]ect of the invention is to improve the methods and compositions heretofore employed for the purposes to which the invention relates.

The introduction into metal of materials adapted to improve the quality of the metal is often attended with dificulty. Many addition agents are sub3ect to the defect of low density. With such agents the proportion of the material actuall moorporated into the bath as distinguishe from being consumed by oxidation at the surface, or absorbed into the slag, is a matter of doubt, because of the tendency of the materials to float on the molten metal. I have found that lead is admirably adapted for use in conjunction with such addition agents as its high density enables it to give weight to compositions containing ingredients which are too light. 7

Lead also has very desirable qualities as a bonding agent for addition agents which are'in comminuted form. Its softness andmalleability enable it to bind such materials into coherent form, this being accomplished for example by mixing the commmuted material with lead in suitable shapes and sizes, and pressing the mixture. Briquetting is, of course, desirable, as comminuted" materials tend to float because of the surface'tension of the bath, and when floating and in a fine state of division, are extremely susceptible to atmospheric oxidation and other destructive influences. The bonding action of lead may also be utilized'by alloy ing it with other addition agents, or by disseminating the latter in divided form throughout a matrix of lead or a lead alloy,

' as more fully described below.

Certain addition agents or scavengers, such as magnesium, are subject to the defect that their action is too energetic, so that it cannot be utilized to the best advantage. With such agents, a diluent is desirable, and

.suming Application; shifter/tanker 3.1921." seriaiitu. 498,447.

lead, being comparatively inert and asthe' liquid state at a temperature. below; those at which most scavengers begin to act, is well adapted tomoderate the action of agents of too intense activity. 'Another aspect of the same effectis the protection against atmospheric-oxidation at the surface of the bath which is afforded by lead. Such reads-1y oxidizable substances as magnesium require such protection, even when they are so agglomerated and weighted that they sink into the bath in a minimum time.

The action of lead 1n promoting fluidity insuspended slag is especially advantageous where a scavenger is employed which, in its scavenging action, gives rise to a solid or liquid substance .in the bath, which substance ,is incapable of combining with the bath but is adapted to unite with lead oxid to form a relatively fluid compound. Silicon may be mentioned as an example of such a scavenger. This element is frequently added to metal baths, for example as an alloy, to remove oxygen and other impurities. The oxygen compoundformed therefrom combines with lead oxid to produce a fusible glass and lead is therefore a particularly valuable auxiliary agent for use in connection with silicon deoxidizers. V

. Lead may also be alloyed with other addition agents. A lead-magnesium alloy is an excellent form in which to add magnesium to steel or other molten metal, the lead givmg the weight which the magnesium lacks,

protecting the magnesium from oxidation atthe surface of the bath, and diluting the magnesium so as to moderate its action on the metal. The density of theialloy can be adjusted by varying its composition, and the alloy need only be cast or out into slugs of convenient size to prepare it for use. The alloy may have a density higher or lower than that of the metal to be treated, de-

pending on the method of using the alloy.

The following example will serve to illustrate the use of a lead-magnesium alloy:

Example I.'1% of an alloy containing 92% lead and 8% magnesium was added to achrome-iron allo the transverse breaking test of the solidi ed metal showing an increase of 20% in strength over a parallel test ladle deoxidized with aluminum. The metal contained no lead and only a trace of,magnes1um,-

chips, shavings or the like. When suitably mixed with the main addition agent] or agents and subjected to pressure, a compact, aggregate of regulatable density is formed,;-

as illustrated by the following example: f

Example II.-10 parts of magnesium shavings are mixed with ,56 arts of lead shot and 34 parts of powder-e manganesesilicon containing about 45% silicon and about 55% manganese, and the mlxture.

pressed into briquets. In this composition, both the magnesium and the lead act as binders, while the lead weights and dilutes both the other ingredients and protects them from oxidation at the surface of the bath."

In accordance with the theory already set out, it is believed that the lead gives rise to substances in the bath which combine with the silica formed by the deoxidizing action of the manganese-silicon, and t-hatlthe cleans-:.f ing of the metal is thereby rendered more mixed with molten lead and the latter arti-,

caused to solidify with unalloyed cles disseminated through it. The lea may also be replaced by a lead alloy, for example,

a lead-magnesium alloy. Somecare is-nec essary to prevent segregation of. the powdered matter, but segregation may be sub.- stantially prevented by reducing the powder to proper fineness and limiting the quantity used. A very effective measure for preventing segregation when an alloy is the suspensory medium, is'to adjust the density of the sus ensory alloy so that it is a little less than t at of the material to be disseminated through it. This can be done, in most cases, by regulating the proportion .of the constituents 1n the alloy. The following examples are cited:

Example [IL-Into a molten alloy con taining 17 parts of magnesium and56 parts of lead, there are stirred 27 parts of the manganese-silicon referred to in Example II, the manganese-silicon being'reduced to such fineness that there is little or no segregation of the manganese-silicon on' Solidilication.

Earample I V.-50 parts-of powdered 80% term-manganese are similarly mixed with a molten alloy containing 16 parts magnesium and 33 parts of lead. 1

From the figures given in Examples II and III, and the disclosure in my United States Patent No. 1,461,643, dated July 10, 1923, it will be apparent that in the final compositions obtained in these examples,

manganese, silicon, and magnesium are pres: ent in proportions which could not be presti('ms. :,r v p y BQforegoing description I have re-' in they metal.

. .i swamin ert emery alloy of thesethree elements. 1$- is often desirable to add, as a single composition, theithree elements referred to .in' amounts outside their alloying range. The

compositionsherein described afford a very convenient n ezms for effecting such addiferred-to lead as an auxiliary'agent, valuable because it enables t11e n1 aterials with which it is associated better to perform the functions for which they are intended. Since lead does not alloy with steel, nor with ferrous alloys in general, when such are treated perature of a steel bath, lead is rapidly volawith compositions containing lead no lead will remain in the bath as alloy. At the temtilized and will-therefore be boiled off or fixed in the slag. Under such conditions it will be seen that the lead does not containinate the metal treated. I believe that the lead itself'has a distinctly favorable action on the bath, as the rising lead vapors agitate the liquid metaland tend to promote the flotation of slag particles by enabling them to extricate themselves from the molten metal.

- A itation tends to liberate ases dissolved In addition 1: e lead vapor,

upon'reaching the surface of the bath and coming into contact with the air, will be oxidized; and the oxid so formed will comblue with the floating slag, increasing its mobility and hence its purifying and protecting action on the bath.

' While I have given what seems tome the most probable explanation of the beneficial action of the compositions described therein, this is merely by way of illustration and "my invention is-m no waydependent on the correctness of the explanation so given.

While the presence of lead in the composite material is preferable in many cases, it

can also be omitted, especially since magnesium in the form of coarse powder or shavings is a good bonding agent for comminuted materials when the latter are mixed with the magnesiumand the mixture subjected to pressure. A mixture containing magnesium, silicon and manganese, outside their allowing proportions and .free from lead, is here cited as'-- Example IL-20- parts of magnesium, as coarse powder or shavings, are mixed with 80 parts manganese-silicon of the composition given under Example II and the mixture pressed into briquets of convenient size. The magnesium. is a suificient binder, especially when used as shavings, and the manganese-silicon serves to weight, protect and dilute the magnesium;

As disclosed in Patent 1,322,158 granted to me Nov. 18, 1919, it is; advantageous when magnesium is usedrasa cleansingagent for metal baths to' use silicon in conjunctiontherewith, in order that. a. fusible product may be formed by. the action of the compo sition on the metal to which it is, added.

The addition of manganese to the magne sium and silicon is also 'disclomd, thethree existing in macroscopic particles and a metallic binder comprising lead.

6. A; composition for treating metal baths,

, comprising'in coherent form a silicon alloy existing in macroscopic particles and a metallic b nder comprising magnesium and elements being formed into an alloy. Other lead alloys containing these three elements are disclosed in my United States Patent No. 1,461,643 referred to above. In the use of all these compositions, the acidic 'oxid formed from the silicon combines with the incompletely allo ed compositions may be prepared in accor ance with the present disclosure.

I am aware that various-known addition agents for steel baths, for example commercial form-manganese, are not strictly homo enous in their microstructure, containing umlissolved microscopic particles of carbids and the like. within my invention as are incompletely alloyed, are distinguished from these materials in that such incompletely alloyed compositions as are herein claimed contain conan alloy of magnesium and lead.

siderable quantities of macrosco ic particles, suspended in a matrix of solidi ed metal, or

. bonded with a compacted metallic binder.

While I have described my invention in connection with certain specific materials and methods, these are cited merely for illustration, and the scope of my invention is defined only by the appended claims.

I claim:

1. A composition for treating metal baths,

comprising in coherent form a main addition agent existing in macroscopic particles and a soft, relatively hea low-melting and relatively inert metallic inder.

2. A composition for treating metal baths comprising in coherent form a main addi tion agent existing in macroscopic particles and a metallic binder comprising lead.

3. A composition for treating metal baths,

comprising in coherent form a main addi-' tion agent and a metallic binder comprising magnesium and lead.

4. A composition for treating metal baths,

which com rises adding thereto an alloy comprising in coherent form a main addi tion agent and a'metallic binder comprising 5. A composition for treating metal baths,

comprising in coherent forms silicon alloy Such compositions falling 4 j 7. A composition for treating metal baths, comprising in coherent form a silicon alloy existing in macroscopic particles and a metallic'binder comprising an alloy of magnesium and lead. I

8. Method of -forming a scavenging composition for metal baths, which comprises adding to molten metals, particles of an addition agent incapable, of completely dissolving in'said' molten metal, and then cooling the metal to solidificationi 9. Method of formin a scavenging composition for metal batis, which comprises adding to molten metal containin lead, particles of an addition agent. incapa is of completely dissolving in said molten metal, and

then cooling the metal to solidification. 10. Method of forming a scavenging composition for metal baths, which comprises adding to a molten lead-magnesium alloy,

particles of a silicon alloy incapable of completely dissolving in said molten alloy, and

then cooling the molten alloy to solidification.

11. Method of forming a scavenging composition for metal baths, which comprises adding 'to' a molten alloy containing a light metal, particles of an addition agent in- B capable of completely dissolving in said molten alloy, said addition agent having a higher density than said light metal, and

the content of said light metal in said molten alloy being so adjusted that the molten alloy has a lower density than said addition agent. 12. Method of scavenging metal baths, which comprises adding thereto magnesium alloyed with a metal adapted to volatilize in the bath. I

13. Method of scavenging metal baths, which comprises adding thereto magnesium alloyed wit a metal adapted to volatilize in the bath and to increase the fluidity of the S1 a l i. Method of scavenging metal baths, which comprises adding thereto a composi tion comprising an alloy containing magnesium and a metal of a materially higher density than the metal of the bath, and adjust- 12 ing the proportions of the constituents of the composition so that the composition will have a density higher than that of the bath.

15. Method of scavenging steel baths,

containing ead and a more active deoxisium 11110131 having a higher than that of t 9 bath, said. alioycontaini";

volatile metal. I I v 17. Method of scavenging Steel baths,

which comprises adding an alloy-of 'Ieadjend magnesium thereto. 18. Method of which comprises adding thereto lead and an addition agent capable of forming an oxidation product which combines with theoxid 4 of lead to form a. fusible slag.

19. Method of treating molten s teel, which comprises adding thereto lead and an addi-f tion agent capable of forming an oxidation product which combines with the oxid of lead to form a fusible slag. 1 i

20. The method of treati molten iron or steel comprising incorporating therewith a treating molten metalt essee/s material containing niegnesium and having "i'aspecific*gmvity her than the molten iron'er steel;

' ,;;21. The methodof treating molten iron or steel comprising incorporating therewith a material containing magnesium and lead.

22, The method of treating molten iron or steel comprising incorporat ng therewith a materialkcontammg magnesium and lead and having ,a specific gravity higher than; 

